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i c. P. HOLLISTER Dec. 6, 1932. LOCALLY CONTROLLING RADIO nacmvme APPARATUS' Re. 18,689

v 5 Sheets-Sheet 1 Original Filed May 11. 192B CZarenceJlZY ZZI/Ster attorney C. P. HOLLISTER 6, 1932, LOCALLY CONTROLLING RADIO RECEIVING APPARATUS Re. 18,689

3 Sheets-Sheet 2 Original. Filed May 11, 1928 7'0 AMPLIFIER mm L 000 GPLA KER CYaren 0e APE/I131?! (Ittorneg C. P. HOLLISTER De 6, LOCALLY CONTROLLING RADIO RECEIVING APPARATUS; R 1

v 1 3 Sheets-Sheet 5 Original FiI'ed May' 11, 1928 r29 v Zhwentor CZarezgae zrzyazzwb (Ittomeg Reissued Dec. 6, 1932 UNITEDSTATES PATENT; OFFICE v CLARENCE r. HOLLISTER, or COLD SPRING, NEW YORK, AssIoNOR To THE BROOKLYN METAL STAMPING CORPORATION, OF BROOKLYN, NEW YORK, A. CORPORATION or ITEW YORK LOCALLY CONTROLLING ADIO ECEIVING AI-I'ARA Us Original No. 1,790,686, dated xaiiuar ev, 1931', Serial No. 279,116, 1111111 m 1 1, 1923. Application! reissue filed November 4,

This invention relates to the control of radio receiving apparatus and particularly to means for causing the apparatus to reproduce at will locally produced sounds, such as human speech or music.

Radio receiving sets or apparatus have heretofore been employed to reproduce not only signals, musical compositions, and speech received by radio waves but also to reproduce phonograph'records. The object of my invention is to provide means for interru'pting at will the operation of a radio' ment of the invention;

Figure 2 is a top plan view of the controller with the cover removed;

Figure 3 is a transverse sectional view on the line 3-3 of Figure 2;

Figure 4 is a fragmentary detail sectional view on the line 4 --4 of Figure 2;

Figure 5 is an illustrative view, partly schematic, showing my invention arranged to interrupt and control a radio receiving apparatus which is adapted to reproduce a' phonograph record;

Figure 6 is a perspective view, partly broken away, of a tube attachment which I may employ in the organization shown in Figure 5;

Figure 7 is a diagrammatic illustration,

, partly schematic, showing my invention ap plied to a radio receiving set using alternatingpurrent thermionic tubes; igure 8 is asectional View of the controller, taken on the line 88 of Figure 3;

Figure 9 is a perspective view of the magnetic system of the controller.

- I have illustrated in Figure 1, the usual conventional diagram ofthe circuits of the 1932. Serial No. 641,324.

detector portion o f a radio receiving set including the antenna, the A and B batteries, the detector tube socket S and the transformer T. In order to connect the local controller-C in circuit with the grid and filament *of the detector tube TU, I provide an adapter AD which is interposed between the tube" and the socket. This adapter becomes an adjunct to the tube and inefiect is a means of separating the plate prong P into two parts and interposing the controller in the gap between the parts.

I have partly broken away the wall or casing of the adapter AD for the purpose of showing the circuit connections. Four prongs depend from the bottom wall 20 of the casing corresponding in position to the prongs of the usual radio tubes so that they 'may be inserted in the corres Onding apertures in the tube socket S o the ordinary radio set. The top orrcover of the casing is provided with apertures arranged in the same manner asthe usual tube socketto receive the prongs depending from the tube.

Secured to or adjacent the inner wall of the cover are four spring contact members 22, 23, 24 and 25, each havinga spring tongue extending into alinement with one of the apertures in'the cover, so that when the prongs of a tube are inserted in the apertures, the

contacts will engage the respective prongs.

The contacts 22, 24 and 25, corresponding to the grid, and filament prongs are connected I with the correspondin prongs de ending fromthe bottom wall 2 0 of thecasi iig; but the contact 23 is not directly connected to the plate prong P, the contact and prong bein connected separately with the controller by conductor wires 26.,and 27, which may be conveniently enclosed in a flexible cord or cable.

. The controller C comprises a magnetic transmitter provided with a vibratory actuator responsive to sound waves, such as a diaphragm ofmagnetic material, and a manually controlled switch or circuit changer, all enclosed in a suitable'non-magnetic housing or casing.

The circuit controller or switch comprises spring arms carrying contacts 30, 31 and 32 and a push-button 34, by which the central contact 31 may be shifted from engagement with contact 30 over to engagement with con: tact 32, the latter being grounded by wire 33 to the non-magnetic metal casing 35, to which the adapter contact 25,is also connected by conductor 28. The terminals of the coil. 36 are connected respectivel to the plate prong of the adapter by wire 2 and to the central switch spring arm by wire 29.

The magneto electric sound responsive device C which operates to superimpose upon the Bbattery circuit variablecurrents corresponding to the sound waves which it is desired to amplify through the medium of the radio re-' amplitude as to overpower the capacity of the reproducing unit and cause a disagreeable break or blast in the sound issuing from y the loud speaker. This fault is common toall prior magneto-electric sound responsive devices. I have devised a magneto device in which this very great defect has been overcome.

My magneto-electric sound responsive device is particularly illustrated in Figures 2, 3,4, 8 and 9. The permanent magnet has a south pole at eitherend and a consequent north pole at the center.v A soft iron core 11.

'of very high permeability extends upwardly from the center and is preferably threaded through a central hole. the core is rigidly braced b a non-magnetic strap 38 beltedto a bracket 39 which is riveted to the bottom of the casing. The airgap between the end of the core and the diaphragm 40 is adjusted with great precision by I means of a tool applied to the inner notched end of core and it IS then permanently secured by means of asealing material 41 covering the end within a cap or annular flange 42. I

Flat steel spring members 43, 43 are held tightly against the ends of the magnet, being wedged between the casing and the ends of the magnet. A flat circular iron ring 45 bears upon the inturned outer ends of the spring members 43, 43 and supports the thin steel disk .40 which forms the vibratory diaphragm. The cover carries a mouth-piece 47. When the cover is forced down in position on the casin it presses the diaphra m and ring inward y against the tension 0 the flat springs 43, 43 so that the diaphragm and ring are held tightlytogether and in firm contact with the I spring members, thereby establishing a good magnetic path for the magnetic flux. As

deas The outer end of stated above, the small airap between the outer end of the core n an the diaphragm is established with great precision to thereby accurately regulate the reluctance of the magnetic circuit. This is adjusted untilthe in strument responds with greatest sensitiveness and clea rness.

- The core member 11. which is of soft iron, such as Swedish iron, possesses a very high permeability so that it permits rapid changes in magnetic flux due to slight changes in the air-gap as the diaphragm is vibrated by sound waves. The currents induced in the coil 36 will vary in frequency and in intensity in proportion to and synchronously with the changes in magnetic flux in the core. While the reluctance of the magnetic path can be fixed or determined with precision for the neutral or normal position of the diaphragm by adj ustin the width of the air-gap to thereby control t e sensitiveness or responsiveness of the'instrument, yet this will not determine the maximum flux which may be suddenly produced in the core when a sudden violent explosion of sound waves strikes the diaphragm. I have found that such a sudden explosive force may so decrease the air-gap as to unduly augment the magnetic flux with a consequent production of an excessive voltage sufiicient to produce a blast or break in the note issuing from the loud speaker unless special means are provided to prevent said excessive increase in the magnetic flux.

Accordingly I have so constructed a certain portion of the magnetic system that its flux carrying capacity is limited to a definite maximum or so that it will become saturated by" a magnetic flux which will .be insufficient to induce a voltage in the generating coil 36 sufficient to produce a break or blast in the sounds issuing from the loud speaker connected to the radio receiving set. I accomplish this.

purpose making the end members 43, 43 of flat spring steel which has a'much greater reluctance than the core member and hence will not respond as quickly to sudden changes 7 and is made of a thickness which limitsthe cross section to dimensions which becomesaturated before the magnetic flux is suflicient to induce the'undesired high voltage. I I have found in practice that it isimpossible to produce a blast in the loud speaker by subjecting the magnetic transmitter of my controller to ,suddenloud or explosive noises;

' The operation of my invention as disclosed in Figure 1 will be apparent from the previous description of the apparatus. The radio tube TU'is inserted in. the adapter AD and the prongs of the latter are then inserted in the apertures in the tube socket S of t heradio receiving set. When the battery switch 49 is closed the set will operateunder the control of the radio waves coming in over "the antenna in the normal manner. It will-be seen that the grid and filament prongs of the troller C, conductor 27 and prong P of the I adapter to the tube socket S.

When it is desired to interrupt the radio reception and to reproduce and amplify local sounds through the radio set, the operator presses with the finger on the switch pin 34,

. set and the loud speaker. I have illustrated thereby'moving contact 31 away-from contact 30 and into engagement with contact.32,

thereby'breaking the circuit from the plate.

of the tube. Vocal or other sounds now entering the mouthpiece of the controller will vibrate the diaphragm 40 and thereby induce alternating electrical potentials corresponding to the sound waves in the generating coil 36 and these in turn will be superposed upon the voltage of the B battery to be amplified in the radio set and reproduced in the loudspeaker. The circuit in which these voltages generated in the coil of the controller are superposed upon the voltage of the B battery may be traced from positive pole of B battery through the primary of transformer T, the plate socketyand prong P of the adapter, conductor 27, generator coil 36,contacts 31 and 32. conductors 33 and 28, contact 25 and prong F of the adapter, conductor 50, A battery back tothe negative pole of B battery. I am thus enabled to locally control the operation of the radio receiving set at will. towinterrupt the reception of the radio waves by the set and to amplify locally produced vocal. musical or other sounds.

Radio receiving sets have heretofore been arranged toreproduce honograph records through the usual amplifier portion of the in Figure 5, the application of my invention to the control. of a radio receiving set when thus used with a pick-up operated by a phonograph record. 1

In the organization shown in Fig. 5, the varying voltages induced in the pick-up device 56 which is being actuated from a phonograph record 57,.are impressed directly upon the grid of the detector tube and control its operation in the same manner as it is usually controlled by the radio waves so that I retain the full amplification derived from the use of this tube. I use the same controller G and adapter AD shown in Figure 1 and previously described. In order to connect the phonograph pick-up device with the grid andfilament'ofthe detector tube, I provide an attachment to be applied to the prongs of the tube, illustrated in Figures 5 and 6. 'A plate 60 of any suitable insulating material is provided with holes positioned to receive the prongs of the tube. Spring contacts g and f are arranged to project through or inalignment with the holes which receive the grid and plate prongs.

These. contacts are connected to suitable binding posts 61 and 62 which receive the ends, of the conductors leading from the pick-up device.

' The operation of the arrangement shown in Figure 5 will be evident. When the tube attachment TA is slipped over the prongs of the tube TU, the latter is inserted in the adapter AD, which is then inserted in the tube socket S. The conductors from the pick-up are then in direct connection with the grid and filament of the tube. The coil 36 and switch contacts 30 and 81 of the con troller are included in the plate circuit. The radio set will therefore reproduce the record of the phonograph record, but may be inter ruptedfor the substitution of vocal or other sounds impressed upon the transmitter of the controller in the same manner as d'e scribed in connection with Figure 1.

It will be evident toengineers and those familiar with radio apparatus that my invention may be used with the alternating current type of radio tube, usually referred to as an A. C. tube. I have shown the arrange.- inent in Figure 7. As is well known, the cathode K of an A. C. tube is connected to the negative pole of the B batter the filament being usedmerely to-radiate heat to the cathode. It is only. necessary to slightly modify the adapter by connecting. the conductor 28 to an intermediate point .between the legs of the ament or heater. I therefore provide a resistance R connecting the heater prongs of the adapter and connect th conductor 28 to its middlepoint. f

. The operation of the arrangement shown in Figure 7 will be understood from the previous description. When the tube has been inserted in the adapter and the latter is inserted in the detector sockets of the radio receiving set, the set will be actuated by the radio waves received over the antenna in the usual manner. When the switch button or pin 34 of the controller is depressed to dis-' connect contact 30 and connect 31 and32, the radio set will then respond to sounds impressed upon the diaphra m of the transmitter. The plate of the tu e is cutout at the open contact 30. The varying potentials induced in the generator coil 36 of'the'transmitter are superposed upon the voltage of the I B battery througha circuitas follows: from positive terminal of B battery through the primary of transformer T, prong P of adjuster AD, conductor 27, coil 36, contacts 31, 32, conductors 33 and 28, to the mid-point of resistance R, throughthe prongs H. H

and A. C. conductors to the grounded minus 4 lapse shown h'ow'it may be used in conjunction with to said. transmitter interposed between the the usual reception of radio waves or in conradio detector tube and its socket, said transjunction with the reproduction of phonoinitter having associated means for subjecting graph records.

' plications will occur to engineers familiar tentials received over the antenna or for elimwith the operation of radio apparatus. Thus inating the plate and subjecting the original my invention may be used in conjunction with plate circuit to currents generated by the the projection apparatus which combine pictransmitter.

tures with vocal sounds, sometimes designated '5. In an apparatus for locally controlling as talking moving pictures, vitaphon'e', etc. a radio receiving apparatus provided with various practical applications will be evident, an antenna connection, a transmitter device such as its use for the school and lecture room, responsive to local sound waves and means Other arrangements and ap the grid circuit of said detector tube to pq-' and for use in calling cabs and private al1t0- providing circuit connections between said Y mobiles at theatre entrances, etc. V 1 transmitter and said radio apparatus, said I have illustrated the use of the adapter transmitter device being provided with in association with the detector tube of a means for subjecting the radio apparatus at radio set but it may be used in other parts will to the control of potentials received over the invention.

of the set and with the power amplifier which the antenna'or to the control of said transis frequently employed 'as an adjunct to a mitter device. radio set. I have illustrated and described a magneto-electric transmitter as the type to a radio set, including the sound actuated which I prefer to use but it will be evident demos and connecting wires, one of said wires to engineers that I may employ other types adapted to be grounded directly or indirectly of transmitters, such. as the microphonic type. to the set, and another adapted for connec- In other words I do not in any mann tion with a tube of the set, and a switch as strict myselfto the particular arrangements nm egral partpf said transmitter for cutdescribed herein for the purpose of disclosing ing o'if the rad eption and Cutting in Y the transmitter. I claim 7. A transmitter and a casing therefor, 1, Apparatus for controlling .3, adapted 120 be connected to a: set, inradio receiving set, comprising an adapter g g h so d actuated device and conha i prongs j t bl i a di d t t nectlng w1res, one of said wires adapted to 6. A transmitter, adapted to be connected,

tube socket to en age the contacts thereof, be g d t y irect y to the set,

and another adapted forconncction with a and provided wit apertures to receive the prongs of a radio tube and with contacts engaged bysaid tube prongs, electric. connections between the contacts and prongs of the adapter, a magnetic transmitter having a generating coil included in one of said connections, and means for eliminating the plate and superposing the transmitter currents directly upon the original plate circuit of said tube. H

2. Means for locally controlling the operation of a radio receiving apparatus, comprising a magnetic transmltter responsive to sound waves and having means for limitin the generated voltages 'to a predetermine maximum value, and switching mechanism operative at will to eliminate the plate of the detector tubeand superpose said sound generated voltages upon the original plate circuit of said tube. J 1

3. The method of operating a radio receiving set which consists in alternatively subjecting it to controlling potentials impressed 'upon the grid of t e detector tube or to locally enerated currents superposed upon the original plate circuit of said tube with the plate eliminated.

4. Apparatus for locally controlling a tube operating to actuate the loud-speaker,

and a switch mounted within the casing for cutting oif the radio reception and cutting in the transmitter.

8. A transmitter for local broadcasting,

ice

to a tube operating to. actuate the loud speaker, and another adapted to begrounded directly or indirectly to the set, and a manually operated switch as an integral part of said transmitter for making and breaking a said connections, to thereby cutoff the radio reception and cut in the local transmitter.

In testimony whereof, I aflix my signature.

. CLARENCE P. HOLLISTER.

radio receiving apparatus provided the usual antenna connection, comprising a magnetic transmitter responsive to local sound waves,'and means. having circu t connections 

